Horribly uncoordinated thoughts from a physics and microbiology student

Monday, June 9, 2008

Never Trust Anything with a Nuclear Envelope

Ok, I may be a bit biased, being a microbiologist and all, but I really believe that prokaryotes are the superior form of life on this planet. Sure they may be referred to as the "lower organisms" and sometimes (somewhat misleadingly) as "less evolved," but these little guys are truly amazing pieces of work.

For one thing, bacteria and archaea have evolved to live in just about every environment imaginable. Now I know what you're thinking: Visions of horny toads in the desert and penguins in the antarctic are floating through your mind. And these adaptations are nothing to ignore, but they can't hold a candle to the prokaryotes' roaring bonfire. Consider the acidophiles and alkaliphiles. These "bugs" live at opposite ends of the pH spectrum, the very low (1-3) and very high (10-12), respectively. Then take a look at the hyperthermophiles who have an optimum growth temperature above 80 degrees Celsius (175 degrees Fahrenheit).

All of these adaptations are impressive in and of themselves, but prokaryotes didn't stop there. No, instead, some have evolved to live in areas of both extremely high temperature and extreme pH. Simply Amazing. And the extreme environments don't stop there. There are organisms that can live in extremes of salinity, oxygen content, and even ionizing radiation. If you look at any corner of the world, you'd be hard-pressed to find one where no prokaryotic life existed.

Another interesting tidbit is eukaryotic dependence on prokaryotes. As you read this, there are bacteria in your intestines synthesizing vitamins that your body can't for you to absorb. Ok, you may say that we don't need them; we can just take multivitamins every morning, but consider this: cows, indeed all ungulates, are incapable of breaking down the cellulose that makes up cell walls in the grass they eat. So how do they digest it? They have special organs in which cultures of microbes break down the cellulose into smaller molecules that the cow is capable of digesting.

If those examples don't impress you much, try this one on for size. Each and every eukaryotic cell depends on its own "domesticated" prokaryote. In humans and all animals, this "domesticated prokaryote" is the mitochondrion. Plants have mitochondria too, but they also harbor chloroplasts, which have prokaryotic cellular origins as well. It is thought (and generally accepted) that these structures began as free-living prokaryotic cells that were engulfed by their larger, nucleus-bearing brethren.

So the next time you reach for the Lysol, take a moment to reflect on the awesomeness of these organisms you are about to wipe from the face of the planet. Don't bother feeling bad though, they wouldn't think twice (or at all in fact) about doing the same to all of us. The difference is, when it comes to one of us wiping the other out completely, they could do it, and we wouldn't stand a chance.